The present invention relates to the field of mechanical vibration mechanisms. In particular, the present invention relates to a device for producing an apparently random vibrational motion, in combination with a means for initiating and terminating such motion, without an external on-off control switch as would find application typically in toys and similar novelty items.
Toys and novelty items are frequently manufactured with the capability to undergo a vibrational motion, adding thereby to the amusement value and consumer appeal. Several examples exist of different means to produce such vibrational motion, as well as several examples of switch devices for initiating and terminating such vibration.
The work of Richard (French patent 2,254,185) describes a toy in the shape of a dog's bone. Vibrational motion is produced by the rotation of a small, battery operated, electric motor inside such bone. The motor rotates an unbalanced load such that the resulting motion causes the motor to vibrate in an apparently random manner when activated. Having this motor attached to the interior surface of the bone causes the entire device to vibrate when activated. The activation means for this device comprises a simple pressure-activated switch positioned in such a location as to make contact and activate the motor when the bone is compressed, typically to a dog's chewing. The resulting vibration of the bone continues for as long as the bone is compressed and terminates at once when compression is removed.
The invention of Halvorson et. al. (U.S. Pat. No. 3,530,617) also uses unbalanced rotation to produce vibration in a toy. However, this invention coordinates two motors rotating at predetermined speeds to impart rotational centrifugal forces to a toy vehicle. The resulting coordinated motion causes the vehicle to move forward. The novelty appeal of this device seems to lie in the generation of forward motion without any apparent external means of propulsion (such as a drive wheel, tread, etc.)
The invention of Martin (U.S. Pat. No. 4,438,588) uses a mercury switch to sense the orientation of a remote controlled ball. Such a mercury switch is used to turn off power when the ball (and toy vehicle contained therein) is inverted.
Hughes (U.S. Pat. No. 4,536,167) discloses a toy using a motor with an unbalanced load to produce a vibrational motion similar to a rocking mechanism as would be used, or example, in a toy submarine. This invention makes use of two switches to control the activation of the motor. A mechanical switch is used in proximity to a asymmetrical inertial fly-wheel which closes intermittently as a protruding portion of said fly-wheel rotates into contact with said switch. The toy also makes use of a mercury switch (or other horizontal-sensing switch such as a ball-in-cage switch) as a mechanism to sense the deviation of the toy from horizontal. Said mercury switch is connected in parallel with said mechanical switch to produce continuous motion.
In contrast to these inventions the present invention uses a single attitude switch (typically a mercury switch) in combination with an unbalanced rotational load. The positioning of the mercury switch is chosen such that, when at rest on a horizontal surface, the object remains at rest indefinitely with no battery drain and no work being performed by the motor. However, when disturbed, the present invention continues in motion indefinitely until there is active intervention by the user. This active intervention take the form of firmly holding the object in a horizontal position for sufficient time that the mercury switch comes to rest in the off position. Thus, the present invention produces no motion until disturbed. Once set in motion, it remains in motion indefinitely. The object returns to rest only when firmly held at rest for (typically) 1 or 2 seconds. All this is accomplished with a single mercury switch internal to said object, and no external switches of any kind. This allows the entire mechanism to be permanently sealed inside a container such as a toy or a can. Except to change the battery, there is no need for the user to have any access whatsoever to the interior of such toy. A typical use for this mechanism is in a toy, substantially in the shape of a standard food can, carrying a label such as "canned earthquake". The novelty amusement value lies in part in the lack of an external switch and the cans apparent "obedience" to physical quieting by the user.